Development of small-sized, high-performance information communication devices such as mobile telephones, electronic dictionaries, and digital video cameras is becoming more and more rapid, not only because semiconductor devices have higher integration and higher speed than ever, but also because those semiconductor devices consume less electric power. In those mobile devices, various kinds of memory cards containing memory devices for storing information are used in an inserted state in a card-edge manner. Not only concavity-type connectors to which those cards are to be inserted and connected, but also concavity-type connectors of the USB (Universal Serial Bus) standard often seen in personal computers are used to mutually control peripheral devices such as printers, mouses, and measuring devices. In recent years, attention is drawn to concavity-type connectors to connect components having developing LEDs mounted thereon, because of the international standardization. Also, to connect multilayer printed boards to each other, there have been structures having concave connecting portions in the multilayer substrates (see Patent Document 1, for example).
Prior Technical Document
Patent Document
Patent Document 1: Japanese Patent Application Laid-open No. 2004-335547